1. Field of the Invention
The present invention relates to a display panel socket which can be preferably used for inspection of the display quality etc. of a liquid crystal display panel, electroluminescence panel, plasma display panel, etc.
2. Description of the Related Art
In general, in the manufacturing process of a liquid crystal display panel etc., the display panel is inspected for the display quality etc. for detecting display defects before connection of peripheral circuits such as driving IC tabs. Accordingly, in this type of inspection, a socket provided with contact members for contact with electrode terminals arranged on the substrate of the display panel has been used. For example, as shown in Japanese Unexamined Patent Publication (Kokai) No. 6-08034, as the contact members to be brought into contact with the electrode terminals of the display panel, conventionally, there have been known those constituted by needle-shaped or wire-shaped probes and contact films comprised of base films having a flexibility and insulation property on which contactors are formed. Along with a rise of density of electrode terminals and increasing fineness of the pitch, the trend is toward use of contact films from the viewpoints of the reliability of contact with the electrode terminals, facility of handling, manufacturing costs, etc.
When contact films are used, in order to bring the contactors on the contact films and the electrode terminals on the substrate of the display panel into contact under a required contact pressure, a film pressing member for pressing the back surface of the contact films and a panel pressing member for pressing the back surface of the substrate of the display panel become necessary. For example, Japanese Unexamined Patent Publication (Kokai) No. 8-233886 of the present assignee discloses a display panel socket provided with a film pressing member made of an elastomer such as rubber, a panel pressing member made of a metal having a substantially lateral U-shaped cross-section with a spring property, and a flexible shutter which moves from a retracted position for opening the area for mounting the display panel to a covered position for covering the top of the display panel and interposed between the panel pressing member and the display panel when moving from the retracted position at which the panel pressing member opens the area for mounting the display panel to the pressing position for pressing the upper surface of the display panel. This panel pressing member made of metal is slidably mounted on the socket body so as to vertically sandwich the socket body and is constituted so as to press the display panel to the contact films via the flexible shutter when moving to the upper surface of the display panel mounted on the contact films.
However, the panel pressing member made of metal having a substantially lateral U-shaped cross-section easily warps when it is formed by pressing or the like. Particularly, the upper piece of the panel pressing member is easily rippled or turned back along the direction of arrangement of the electrode terminals, therefore it becomes difficult to uniformly press the upper surface of the display panel. This becomes a cause of deterioration of the reliability of contact between the electrode terminals on the substrate of the display panel and the contactors on the contact films. Further, where both of the panel pressing member and the shutter are made of metal, metal abrasion powder is liable to be generated due to the sliding movement between the metals. This will adhere to the contactors on the contact films and become a cause of obstructing contact between the electrode terminals and the contactors.